大倾角煤层采动巷道断面形状选择与支护参数设计OA

The mining roadways in steeply inclined coal seams were disturbed by multiple factors such as adjacent goafs and section coal pillars during mining.The stress environment of roadway surrounding rocks became relatively complex,making it difficult to effectively control surrounding rock deformation.Disasters including rib spalling and roof fall were easily induced,which seriously restricted the normal advancement of working faces and safe production of mines.To address the above problems,No.3123 return airway of mining roadways in steeply inclined coal seams at Lvshuidong Mine was taken as the engineering background.Theoretical analysis,numerical calculation and field measurement were combined to systematically investigate the failure characteristics of surrounding rocks of roadways with arched and asymmetrical roof cross-sections under mining influences in steeply inclined coal seams,and the distribution characteristics of surrounding stress were clarified.The results showed that the roadway with asymmetrical roof cross-section significantly improved the stress distribution of surrounding rocks,reduced the development range of plastic zones and decreased the maximum failure depth under mining influences in steeply inclined coal seams,and thus was more conducive to roadway stability.Accordingly,based on the structural characteristics of asymmetrical roof roadway cross-section,a non-uniformly arranged active-passive collaborative bolt and cable support system was designed and implemented.Multi-point displacement monitoring was conducted in deep roof strata simultaneously.Field measured data indicated that the cumulative roof displacement during excavation disturbance was stably controlled within 100 mm.Deformation was concentrated in soft coal zones,and the overall stability of surrounding rocks was effectively guaranteed.